1. Field of Invention
This invention relates to a method and apparatus for discharging a food material, more particularly to one for discharging a boiled rice material or other viscous materials in producing boiled rice balls and rice dumplings covered by bean jam.
2. Prior Art
Japanese Patent Publication No. 39-12276 discloses an apparatus for discharging a food material downward. The apparatus comprises three conical rollers disposed in upright positions to form a funnel-shaped space to receive the food material. In FIG. 1 (only two of the three rollers are shown), to illustrate a sectional view of the apparatus, these conical rollers 2 are rotated in the same direction at the same speed. The peripheral speed of each roller at a position indicated by an arrow A is faster than that at a position indicated by an arrow B. Therefore, the food material 4 charged into the funnel-shaped space, located at the position A, is subjected to a force in the circumferential direction, which force is greater than the force that the food material located at the position B is subjected to. Therefore, as shown by an arrow C, the food material is pulled downward.
In the prior-art apparatus some viscous food materials tend to slip on the surfaces of the conical rollers, so that the food materials cannot be smoothly fed downward. Furthermore, a rod-like food material 5 discharged from the funnel-shaped space has been not uniformly shaped. Namely, stably discharging the food material has been required. U.S. Pat. No. 5,385,074 discloses an apparatus and method for cutting helically-shaped potato pieces. The feed section of the apparatus comprises a plurality of rods disposed to form a funnel-shaped space. Each rod has a spirally-shaped outer surface. Each pair of adjacent rods is adapted to rotate in the same direction. However, as in FIG. 2, each pair of adjacent rods is adapted to rotate in the direction opposite to that of the other pair of adjacent rods. Namely, the rods do not all rotate in the same direction. Therefore, a food material within the funnel-shaped space would not be conveyed downward smoothly.